1. Field of the Invention
The invention relates to a pattern and to a method for forming a pattern using a printing process, and particularly to a method for forming a pattern which alleviates the problem of an uneven pattern generated as a substrate becomes larger.
2. Description of the Related Art
In display devices, particularly in flat panel display devices, pixels are arranged in a matrix. Flat panel devices, such as LCD devices, have an active device, such as Thin Film Transistors (hereinafter, TFTs) positioned in respective pixels for driving the pixels in the display devices. This method of driving the display device is called the active matrix driving method because the active devices are arranged in the respective pixels aligned in a matrix form.
FIG. 1 shows a plan view of a pixel in a conventional LCD device using the active matrix method. The active device is a TFT 10. Gate lines 2 are arranged lengthwise and data lines 4 are arranged widthwise to define a pixel. The TFT 10 for independently controlling the driving of the respective pixel is formed near where one of the gate lines and one of the data lines cross over each other. The TFT 10 includes a gate electrode 2a, which is connected with one of the gate lines 2, a semiconductor 5 that is formed on the gate electrode 2a, and source and drain electrodes 4a and 4b that are formed on the semiconductor layer 5. The TFT 10 activates when a scan signal is applied to the gate electrode 2a by one of the gate lines 2. In the pixel, a pixel electrode 7, which is connected to the drain electrodes 4b, is supplied with an image signal through the source and drain electrodes 4a and 4b when the semiconductor layer 5 is activated by the gate electrode 2a. The pixel electrode 7 is connected with the drain electrode 4b through the first contact hole 8a. A storage line 6 and a storage electrode 11, which overlaps the storage line 6, are positioned in the pixel defined by the gate line 2 and the data line 4 to form a storage capacitor Cst. The storage electrode 11 is connected with the pixel electrode 7 through a second contact hole 8b. 
FIG. 2 is a cross-sectional view taken along section line I-I′ of FIG. 1 showing a TFT 10 and storage capacitor Cst positioned inside the pixel. As shown in FIG. 2, the TFT 10 includes a substrate 1 made of transparent insulating material (such as glass), a gate electrode 2a formed on the substrate 1, a gate insulating layer 13 deposited over the entire substrate 1, a semiconductor layer 5 formed over the gate insulating layer 13 and source/drain electrodes 4a and 4b formed over the semiconductor layer 5, a passivation layer 15 formed over the source/drain electrodes 4a and 4b to protect the device, and a pixel electrode 7 connected with the drain electrode 4b through the first contact hole 8a. 
The storage capacitor Cst includes a storage line 6 formed during the same series of patterning processes as the gate electrode 2a of the TFT, and a storage electrode 11 formed during the same series of patterning processes as the source and drain electrodes 4a and 4b. A gate insulating layer 13 is formed between the storage line 6 and storage electrode 11. A second contact hole 8b for exposing a part of the storage electrode 11 is formed in the passivation layer 15. The storage electrode 11 is electrically connected with the pixel electrode 7 through the second contact hole 8b. The storage capacitor Cst charges via a gate voltage while a gate signal is applied to the gate electrode 2a, and then holds the charge until the gate electrode 2 is selected in the next frame to prevent voltage change of the pixel electrode 7.
The LCD device described above is fabricated by a photo-mask process, and the photo-mask process includes a series of processes such as photo-resist application, arrangement and exposure, development, cleaning, etc.
FIGS. 3A-3C are views illustrating a method for forming a pattern in the photo-mask process. First, as shown in FIG. 3A, a substrate 30 including an etching object layer is provided. A photo-resist layer 31 of polymer resin is evenly applied on the substrate 30 through a spin coating or a roll coating method. Next, as shown in FIG. 3B, the photo-resist layer 31 is blocked by a mask 33 on which a non-transparent area for the light is selectively formed, and then, UV light (arrows in FIG. 3B) is radiated to expose the photo-resist layer 31 except the blocked area. Next, as shown in FIG. 3C, the photo-resist layer 31 on which the ultraviolet light has radiated is developed to form a photo-resist pattern 31a selectively remaining on the substrate 30. After that, the etching object layer (not shown) formed on the substrate 30 is etched by using the photo-resist pattern 31a as a mask, and therefore, the desired pattern is formed.
However, according to a related photo-mask process, expensive equipment such as a mask and the exposing apparatus is required. Therefore, the production cost increases. Also, aligning the mask and the substrate exactly becomes difficult due to the limitations of the exposing apparatus in the exposure process. Therefore, there is a limit in forming a fine pattern requiring a high degree of accuracy. Moreover, since there is a limited exposure area of the exposing apparatus in the photo processing of the display device, the screen must be divided to fabricate a display device having a larger area. Therefore, the photo process must be repeated many times. The productivity is accordingly lowered, and thus it becomes difficult to meet the demand for larger substrate displays.